1. Field of the Invention
The present invention relates to an illumination apparatus and a projection type display apparatus and, more particularly, to a projector which projects an image (light) supplied from a liquid crystal display element or from a display element of any other type. The invention is suitably applicable to liquid crystal projectors and the like.
2. Related Background Art
A variety of proposals have been made heretofore as to the technology for the liquid crystal projectors constructed to illuminate a liquid crystal panel (liquid crystal display element) with light from a light source and enlarge and project an image based on transmitted light or reflected light modulated by and emerging from the liquid crystal panel, through a projection lens onto a screen.
A TN (Twist Nematic) liquid crystal panel, which is often used in the liquid crystal projectors, is normally provided with polarizing filters such as polarizers, analyzers, or the like before and after a liquid crystal layer.
The polarizing filters have such characteristics as to transmit only a specific polarization component out of incident light but intercept a polarization component whose polarization direction is perpendicular thereto. For this reason, in the liquid crystal projectors, at least half of the light from the light source was intercepted at the polarizing filter on the light incident side of the liquid crystal panel and thus brightness of the image projected on the screen tended to become lowered.
As an illumination apparatus for the liquid crystal projectors, for example, Japanese Patent Application Laid-Open No. 9-311297 suggests the illumination apparatus that uniformly illuminates an area to be illuminated while increasing the utilization efficiency of light from the light source, using polarization converting elements for converting the incident light of non-polarized light into beams of linearly polarized light polarized in a specific direction and two lens arrays (optical integrators) placed in series for uniformly illuminating the area on the surface to be illuminated.
FIG. 10 is a schematic diagram to show the major part of the illumination apparatus suggested in the above Japanese application. In FIG. 10, a polarization generator 20 has a first optical element 200 for creating a plurality of intermediate beams 202 (condensed images 203) spatially separated from each other, from light emitted from a light source section 10 consisting of a light source 101 and a parabolic mirror 102, and a second optical element 300 placed near the position of convergence of the plurality of intermediate beams 202 and having a polarization separating unit array 320 consisting of a polarization separating film array 330 for spatially separating each intermediate beam 202 into two kinds of polarized light beams having respective polarization directions different from each other, a half-wave phase plate array 381 for aligning the polarization direction of the polarized beams of the first kind with that of the polarized beams of the second kind to form linearly polarized light beams of one kind, and a reflecting surface array 332, a condenser lens array 310 consisting of a plurality of condenser lenses 311, and an exit-side lens.
In the first optical element 200, beam splitting lenses 201 arranged adjacently in the Y-direction are placed in a shifted state from each other in the X-direction each by a distance corresponding to approximately a half length of the array pitch thereof in the X-direction, which can improve nonuniformity of light intensity distribution of the light from the light source. In addition, the above Japanese application also discloses a color liquid crystal projector having the polarization generator illustrated in FIG. 10, a color separating means, three liquid crystal panels, a color combining means, and a projection lens.
In each of the embodiments proposed in the above Japanese application, there is no numerical data of the illumination optical system disclosed and it is thus indefinite as to the relation between the focal length of the parabolic reflector and the focal length of the first lens array and the like.
For this reason, designed values (configurations) for yielding the best illumination efficiency were unknown. The projection type display device of FIG. 12 in the above Japanese application also had the drawback of poor light-condensing nature of light onto the entrance pupil of the projection lens, because there was no condenser lens near the liquid crystal panel.
Further, it also describes nothing about detailed structure of the microlenses used for increasing an aperture ratio of the liquid crystal panel.
An object of the present invention is to provide an illumination apparatus and a projection type display apparatus with higher light utilization efficiency than before.
An illumination apparatus according to one aspect of the present invention is an illumination apparatus comprising a light-collecting reflector, a light source placed at a position of a focal point of the reflector, a first lens array for condensing light reflected by the reflector, a second lens array disposed at or near a position of a rear focal point of the first lens array, and an optical system for illuminating a surface to be illuminated, with multiple beams from the second lens array, said illumination apparatus satisfying the following condition:
0.7 less than K1 less than 1.3xe2x80x83xe2x80x83(1)
where K1=(Larcxc3x97flyf1/2fm)/(Lfly2p/2)
where Larc: a length of a light-emitting portion of said light source along a direction of the optical axis,
flyf1: a focal length of said first lens array,
fm: a focal length of said light-collecting reflector, and
Lfly2p: a length along a longitudinal direction of an entrance surface of each lens of said second lens array.
Another illumination apparatus according to a further aspect of the present invention is an illumination apparatus comprising a first lens array for condensing light from a light source, a second lens array disposed at or near a position of a rear focal point of the first lens array, a first optical system for condensing multiple beams from the second lens array, and a second optical system for illuminating a surface to be illuminated, with said multiple beams from the first optical system, said illumination apparatus satisfying the following condition:
0.95 less than K2 less than 1.15xe2x80x83xe2x80x83(2)
where K2=(Lfly1pxc3x97fc12/flyf2)/Ldsp
where Ldsp: a diagonal length of said surface to be illuminated,
flyf2: a focal length of said second lens array,
fc12: a composite focal length of said first lens system and said second lens system, and
Lfly1p: a diagonal length of each lens of said first lens array.
Another illumination apparatus according to a further aspect of the present invention is an illumination apparatus comprising a first lens array for condensing light from a light source, a second lens array disposed at or near a position of a rear focal point of the first lens array, a first optical system for condensing multiple beams from the second lens array, and a second optical system for illuminating a surface to be illuminated, with the multiple beams from the first optical system, said illumination apparatus satisfying the following condition:
0.9 less than K3 less than 1.4xe2x80x83xe2x80x83(3)
where K3=fc1/fc2
where fc1: a focal length of said first optical system, and
fc2: a focal length of said second optical system.
Another illumination apparatus according to a further aspect of the present invention is an illumination apparatus comprising a first lens array for condensing light from a light source, a second lens array disposed at or near a position of a rear focal point of the first lens array, a first optical system for condensing multiple beams from the second lens array, and a second optical system for illuminating a display device with the multiple beams from the first optical system, said display device comprising a display part in which a plurality of pixels of a rectangular shape are arrayed, and a microlens array placed on the light incidence side of the display part, said illumination apparatus satisfying the following condition:
0.6 less than K4 less than 1.6xe2x80x83xe2x80x83(4)
where K4=(Dmicro/F12c)/Lop
where F12c: a composite F-number of said first optical system and said second optical system,
Dmicro: an equivalent air distance from principal points of microlenses of said microlens array on the side of said display part, to apertures of the pixels of the display device, and
Lop: an aperture width along a longitudinal direction of the pixels of said display device.
Another illumination apparatus according to a further aspect of the present invention is an illumination apparatus comprising a first lens array for condensing light from a light source, a second lens array disposed at or near a position of a rear focal point of the first lens array, and an optical system for illuminating an image display device with multiple beams from the second lens array, said image display device comprising a display part in which a plurality of pixels are arrayed, and a microlens array placed on the light incidence side of the display part, said illumination apparatus satisfying the following condition:
2 less than K5 less than 4.5xe2x80x83xe2x80x83(5)
where K5=fmicro/Dmicro
where Dmicro: an equivalent air distance from principal points of microlenses of said microlens array on the display part side of said display device, to apertures of the pixels of said display device, and
fmicro: a focal length of the microlenses.
A projection type display apparatus according to a further aspect of the present invention is a projection type display apparatus comprising a first lens array for condensing light from a light source, a second lens array disposed at or near a position of a rear focal point of the first lens array, a first optical system for condensing multiple beams from the second lens array, a second optical system for illuminating an image display device with the multiple beams from the first optical system, said image display device comprising a display part in which a plurality of pixels are arrayed, and a microlens array placed on the light incidence side of the display part, and a projection optical system for projecting image light from the image display device, said projection type display apparatus satisfying the following condition:
0.6 less than K6 less than 1.5xe2x80x83xe2x80x83(6)
where K6=Fpj/F12c
where F12c: a composite F-number of said first optical system and said second optical system, and
Fpj: an F-number of said projection optical system.
Another projection type display apparatus according to a further aspect of the present invention is a projection type display apparatus comprising a first lens array for condensing light from a light source, a second lens array disposed at or near a position of a rear focal point of the first lens array, an optical system for condensing multiple beams from the second lens array and illuminating an image display device therewith, said image display device comprising a display part in which a plurality of pixels are arrayed, and a microlens array placed on the light incidence side of the display part, and a projection optical system for projecting image light from the display device, said projection type display apparatus satisfying the following condition:
0.35 less than K7 less than 0.85xe2x80x83xe2x80x83(7)
where K7=Fpj/Fmicro
where Fpj: an F-number of said projection optical system, and
Fmicro: an F-number of microlenses of said microlens array.
Another illumination apparatus according to a further aspect of the present invention is an illumination apparatus comprising a first lens array for condensing light from a light source, a second lens array disposed at or near a position of a rear focal point of the first lens array, and an optical system for condensing multiple beams from the second lens array and illuminating an image display device therewith, said image display device comprising a display part in which a plurality of pixels of a rectangular shape are arrayed, and microlens arrays placed on the light incidence side and on the light emergence side of the display part, said illumination apparatus satisfying the following conditions:
1.3 less than K8 less than 2.5xe2x80x83xe2x80x83(8)
1.3 less than K9 less than 2.5xe2x80x83xe2x80x83(9)
where K8=fmicrok/Dmicrok and
K9=fmicros/Dmicros
where fmicrok: a focal length of microlenses of said microlens array on said light incidence side,
Dmicrok: a distance between principal points on the side of said display part, of said microlenses on said light incidence side and apertures of the pixels of said display part,
fmicros: a focal length of microlenses of said microlens array on said light emergence side, and
Dmicros: a distance between principal points on the side of said display part, of said microlenses on said light emergence side and the apertures of the pixels of said display part.
Another projection type display apparatus according to a further aspect of the present invention is a projection type display apparatus comprising a first lens array for condensing light from a light source, a second lens array disposed at or near a position of a focal point of the first lens array, a first optical system for condensing multiple beams from the second lens array, a second optical system for illuminating an image display device with the multiple beams from the first optical system, said image display device comprising a display part in which a plurality of pixels are arrayed, and a projection optical system for projecting image light from the image display device, said projection type display apparatus satisfying the following condition:
0.6 less than K10 less than 1.6xe2x80x83xe2x80x83(10)
where K10=Fpj/F12c
where F12c: a composite F-number of said first optical system and said second optical system, and
Fpj: an F-number of said projection optical system.
Another projection type display apparatus according to a further aspect of the present invention is a projection type display apparatus comprising a first lens array for condensing light from a light source, a second lens array disposed at or near a position of a rear focal point of the first lens array, an optical system for condensing multiple beams from the second lens array and illuminating an image display device therewith, said image display device comprising a display part in which a plurality of pixels are arrayed, and microlens arrays placed on the light incidence side and on the light emergence side of the display part, and a projection optical system for projecting image light from the image display device, said projection type display apparatus satisfying the following conditions:
0.7 less than K11 less than 1.2xe2x80x83xe2x80x83(11)
0.7 less than K12 less than 1.2xe2x80x83xe2x80x83(12)
where K11=Fpj/Fmicrok and
K12=Fpj/Fmicros
where Fpj: an F-number of said projection optical system,
Fmicrok: an F-number of microlenses of said microlens array on said light incidence side, and
Fmicros: an F-number of microlenses of said microlens array on said light emergence side.
In a preferred form of the illumination apparatus described above, a polarization converting element is provided on the side of a light exit surface of said second lens array.
In a preferred form of the projection type display apparatus described above, a polarization converting element is provided on the side of a light exit surface of said second lens array.
In a preferred form of the above illumination apparatus, said light-collecting reflector is comprised of a parabolic reflector.
In a preferred form of the above illumination apparatus, said light source is located at or near the focal point of the parabolic reflector and said reflector outputs nearly parallel beams.
In a preferred form of the above projection type display apparatus, said light source is located at or near the focal point of the parabolic reflector and said reflector outputs nearly parallel beams.
Another projection type display apparatus according to a further aspect of the present invention is a projection type display apparatus which projects image information from a liquid crystal panel placed at a surface to be illuminated, which is illuminated by the illumination apparatus as set forth, through a projection lens.
Another illumination apparatus according to a further aspect of the present invention is an illumination apparatus comprising a first lens array for condensing light from a light source, a second lens array disposed at or near a position of a rear focal point of the first lens array, and an optical system for illuminating an image display device with multiple beams from the second lens array, said image display device comprising a display part in which a plurality of pixels are arrayed, and a microlens array placed on the light incidence side of the display part, wherein a plurality of microlenses constituting the microlens array are comprised of a stack of plural layers, a layer having the highest refractive index out of the plural layers has a lens surface convex on the light incidence side, and an index difference between refractive indices of media on the both sides of the lens surface is not less than 0.1.
Another illumination apparatus according to a further aspect of the present invention is an illumination apparatus comprising a first lens array for condensing light from a light source, a second lens array disposed at or near a position of a rear focal point of the first lens array, and an optical system for illuminating an image display device with multiple beams from the second lens array, said image display device comprising a display part in which a plurality of pixels are arrayed, and a microlens array placed on the light incidence side of the display part, wherein each microlens constituting the microlens array comprises two or more refracting surfaces having light condensing action.
Another illumination apparatus according to a further aspect of the present invention is an illumination apparatus comprising a first lens array for condensing light from a light source, a second lens array disposed at or near a position of a rear focal point of the first lens array, and an optical system for illuminating an image display device with multiple beams from the second lens array, said image display device comprising a display part in which a plurality of pixels are arrayed, and a microlens array placed on the light incidence side of the display part, wherein said microlens array is comprised of a stack of plural layers and a layer having the highest refractive index out of the plural layers is of a double-convex shape.
Another illumination apparatus according to a further aspect of the present invention is an illumination apparatus comprising a first lens array for condensing light from a light source, a second lens array disposed at or near a position of a rear focal point of the first lens array, and an optical system for illuminating an image display device with multiple beams from the second lens array, said image display device comprising a display part in which a plurality of pixels are arrayed, and microlens arrays placed on the light incidence side and on the light emergence side of the display part, wherein a layer having the highest refractive index out of layers forming each lens of the microlens array on the light incidence side has a lens surface convex on the light incidence side and an index difference between refractive indices of media on the both sides of the lens surface of the lens is not less than 0.1 and wherein a layer having the highest refractive index out of layers forming each lens of the microlens array on the light emergence side has a lens surface convex on the light emergence side and an index difference between refractive indices of media on the both sides of the lens surface of the lens is not less than 0.2.
Another illumination apparatus according to a further aspect of the present invention is an illumination apparatus comprising a first lens array for condensing light from a light source, a second lens array disposed at or near a position of a rear focal point of the first lens array, and an optical system for illuminating an image display device with multiple beams from the second lens array, said image display device comprising a display part in which a plurality of pixels are arrayed, and microlens arrays placed on the light incidence side and on the light emergence side of the display part, wherein each of the microlens arrays is comprised of a stack of plural layers and a layer having the highest refractive index out of the plural layers is of a double-convex shape.
Another illumination apparatus according to a further aspect of the present invention is an illumination apparatus comprising a first lens array for condensing light from a light source, a second lens array disposed at or near a position of a rear focal point of the first lens array, and a lens system for illuminating an image display device with multiple beams from the second lens array, said image display device comprising a display part in which a plurality of pixels are arrayed, and microlens arrays placed on the light incidence side and on the light emergence side of the display part, wherein each lens of the microlens arrays on the light incidence side and on the light emergence side comprises two or more refracting surfaces having light condensing action.
In a preferred form of the illumination apparatus described above, a polarization converting element is provided on the side of a light exit surface of said second lens array.
In a preferred form of the above illumination apparatus, said light source is located at or near the focal point of a parabolic reflector and said reflector outputs nearly parallel beams.
Another projection type display apparatus according to a further aspect of the present invention is a projection type display apparatus which projects image information from a liquid crystal panel placed at a surface to be illuminated, which is illuminated by the illumination apparatus as set forth, through a projection lens.
Another illumination apparatus according to a further aspect of the present invention is an illumination apparatus comprising a first optical system for condensing light from a light source, and a second optical system for illuminating a surface to be illuminated, with beams from the first optical system, said illumination apparatus satisfying the following condition:
0.9 less than K3 less than 1.4xe2x80x83xe2x80x83(3)
where K3=fc1/fc2
where fc1: a focal length of said first optical system, and
fc2: a focal length of said second optical system.
Another illumination apparatus according to a further aspect of the present invention is an illumination apparatus comprising a first optical system for condensing light from a light source, and a second optical system for condensing light from the first optical system and illuminating an image display device therewith, said image display device comprising a display part in which a plurality of pixels of a rectangular shape are arrayed, and a microlens array placed on the light incidence side of the display part, said illumination apparatus satisfying the following condition:
0.6 less than K4 less than 1.6xe2x80x83xe2x80x83(4)
where K4=(Dmicro/F12c)/Lop
where F12c: a composite F-number of said first optical system and said second optical system,
Dmicro: an equivalent air distance from principal points on the side of said display part, of said microlens array, to apertures of the pixels of said display part, and
Lop: an aperture width along a longitudinal direction of the pixels of said display part.
Another illumination apparatus according to a further aspect of the present invention is an illumination apparatus comprising an optical system for illuminating an image display device with light from a light source, said image display device comprising a display part in which a plurality of pixels are arrayed, and a microlens array placed on the light incidence side of the display part, said illumination apparatus satisfying the following condition:
xe2x80x832 less than K5 less than 4.5xe2x80x83xe2x80x83(5)
where K5=fmicro/Dmicro
where Dmicro: an equivalent air distance from principal points on the side of said display part, of said microlens array, to apertures of the pixels of said display part, and
fmicro: a focal length of said microlens array.
Another projection type display apparatus according to a further aspect of the present invention is a projection type display apparatus comprising a first optical system for condensing light from a light source, a second optical system for illuminating an image display device with beams from the first optical system, said image display device comprising a display part in which a plurality of pixels are arrayed, and a microlens array placed on the light incidence side of the display part, and a projection optical system for projecting image information from the image display device, said projection type display apparatus satisfying the following condition:
0.6 less than K6 less than 1.5xe2x80x83xe2x80x83(6)
where K6=Fpj/F12c
where F12c: a composite F-number of said first optical system and said second optical system, and
Fpj: an F-number of said projection optical system.
Another projection type display apparatus according to a further aspect of the present invention is a projection type display apparatus comprising an optical system for condensing light from a light source and illuminating an image display device therewith, said image display device comprising a display part in which a plurality of pixels are arrayed, and a microlens array placed on the light incidence side of the display part, and a projection optical system for projecting image information from the image display device, said projection type display apparatus satisfying the following condition:
0.35 less than K7 less than 0.85xe2x80x83xe2x80x83(7)
where K7=Fpj/Fmicro
where Fpj: an F-number of said projection optical system, and
Fmicro: an F-number of said microlens array.
Another illumination apparatus according to a further aspect of the present invention is an illumination apparatus comprising an optical system for condensing light from a light source and illuminating an image display device therewith, said image display device comprising a display part in which a plurality of pixels of a rectangular shape are arrayed, and microlens arrays placed on the light incidence side and on the light emergence side of the display part, said illumination apparatus satisfying the following conditions:
1.3 less than K8 less than 2.5xe2x80x83xe2x80x83(8)
1.3 less than K9 less than 2.5xe2x80x83xe2x80x83(9)
where K8=fmicrok/Dmicrok and
K9=fmicros/Dmicros
where fmicrok: a focal length of said microlens array on said light incidence side,
Dmicrok: a distance between principal points on the side of said display part, of said microlens array on said light incidence side and apertures of the pixels of said display part,
fmicros: a focal length of said microlens array on said light emergence side, and
Dmicros: a distance between principal points on the side of said display part, of said microlens array on said light emergence side and the apertures of the pixels of said display part.
Another projection type display apparatus according to a further aspect of the present invention is a projection type display apparatus comprising a first optical system for condensing light from a light source, a second optical system for illuminating an image display device with beams from the first optical system, said image display device comprising a display part in which a plurality of pixels are arrayed, and a projection optical system for projecting image information from the image display device, said projection type display apparatus satisfying the following condition:
0.6 less than K10 less than 1.6xe2x80x83xe2x80x83(10)
where K10=Fpj/F12c
where F12c: a composite F-number of said first optical system and said second optical system, and
Fpj: an F-number of said projection optical system.
Another projection type display apparatus according to a further aspect of the present invention is a projection type display apparatus comprising an optical system for condensing light from a light source and illuminating an image display device therewith, said image display device comprising a display part in which a plurality of pixels are arrayed, and microlens arrays placed on the light incidence side and on the light emergence side of the display part, and a projection optical system for projecting image information from the image display device, said projection type display apparatus satisfying the following conditions:
0.7 less than K11 less than 1.2xe2x80x83xe2x80x83(11)
0.7 less than K12 less than 1.2xe2x80x83xe2x80x83(12)
where K11=Fpj/Fmicrok and
K12=Fpj/Fmicros
where Fpj: an F-number of said projection optical system,
Fmicrok: an F-number of said microlens array on said light incidence side, and
Fmicros: an F-number of said microlens array on said light emergence side.
In a preferred form of the illumination apparatus described above, said light source is located at or near the focal point of a parabolic reflector and said reflector outputs nearly parallel beams.
In a preferred form of the projection type display apparatus described above, said light source is located at or near the focal point of a parabolic reflector and said reflector outputs nearly parallel beams.
Another projection type display apparatus according to a further aspect of the present invention is a projection type display apparatus which projects image information from a liquid crystal panel placed at a surface to be illuminated, which is illuminated by the illumination apparatus as set forth, through a projection optical system.
Another illumination apparatus according to a further aspect of the present invention is an illumination apparatus comprising an optical system for illuminating an image display device with light from a light source, said image display device comprising a display part in which a plurality of pixels are arrayed, and a microlens array placed on the light incidence side of the display part, wherein said microlens array is comprised of a stack of plural layers, a layer having the highest refractive index out of the plural layers has a lens surface convex on the light incidence side, and an index difference between refractive indices of media on the both sides of the lens surface of the lens is not less than 0.1.
Another illumination apparatus according to a further aspect of the present invention is an illumination apparatus comprising an optical system for illuminating an image display device with light from a light source, said image display device comprising a display part in which a plurality of pixels are arrayed, and a microlens array placed on the light incidence side of the display part, wherein each microlens constituting said microlens array comprises two or more refracting surfaces having light condensing action.
Another illumination apparatus according to a further aspect of the present invention is an illumination apparatus comprising an optical system for illuminating an image display device with light from a light source, said image display device comprising a display part in which a plurality of pixels are arrayed, and a microlens array placed on the light incidence side of the display part, wherein said microlens array is comprised of a stack of plural layers and a layer having the highest refractive index out of the plural layers comprises lenses of a double-convex shape.
Another illumination apparatus according to a further aspect of the present invention is an illumination apparatus comprising an optical system for illuminating an image modulating device with light from a light source, said image modulating device comprising a display part in which a plurality of pixels are arrayed, and microlens arrays placed on the light incidence side and on the light emergence side of the display part, wherein a layer having the highest refractive index out of layers forming said microlens array on the light incidence side has a lens surface convex on the light incidence side and an index difference between refractive indices of media on the both sides of the lens surface is not less than 0.1 and wherein a layer having the highest refractive index out of layers forming the microlens array on the light emergence side has a lens surface convex on the light emergence side and an index difference between refractive indices of media on the both sides of the lens surface is not less than 0.2.
Another illumination apparatus according to a further aspect of the present invention is an illumination apparatus comprising an optical system for illuminating an image display device with light from a light source, said image display device comprising a display part in which a plurality of pixels are arrayed, and microlens arrays placed on the light incidence side and on the light emergence side of the display part, wherein each of said microlens arrays is comprised of a stack of plural layers and a layer having the highest refractive index out of the plural layers forming the microlens array comprises lenses of a double-convex shape.
Another illumination apparatus according to a further aspect of the present invention is an illumination apparatus comprising an optical system for illuminating an image display device with light from a light source, said image display device comprising a display part in which a plurality of pixels are arrayed, and microlens arrays placed on the light incidence side and on the light emergence side of the display part, wherein each of the microlens array on the light incidence side and the microlens array on the light emergence side is an array of lenses, each lens comprising two or more refracting surfaces having light condensing action.
In a preferred form of the illumination apparatus described above, said light source is located at or near the focal point of a parabolic reflector and said reflector outputs nearly parallel beams.
Another projection type display apparatus according to a further aspect of the present invention is a projection type display apparatus which projects image information from a liquid crystal panel placed at a surface to be illuminated, which is illuminated by the illumination apparatus as set forth, through a projection optical system.